The USPS will only communicate via phone. I think they have a problem with putting things in writing.
Anyway, All Sunset shipping cartons have labels at both ends describing the contents and they are almost impossible to remove. If you have ever received anything from Sunset or one of their dealers you have seen these labels. These labels not only describe the contents but also have Sunset's address on them. There are also descriptions on the inner cartons which have Sunset's address and a owners manual with Sunset's phone number. If they had done as was described above and opened the package and found it's contents to be as described on the shipping carton then they could have, at a minimum, contacted Sunset to see if it they had shipped it. But not even that was done.